Globally, 241 million (30%) school aged children are iodine deficient. Historically, the UK and Ireland were believed to be iodine sufficient but concern has been expressed in the last decade regarding the iodine status of the UK and Irish populations. A study of Irish women in 2004 reported 55% of pregnant women in their sample population to be moderately iodine deficient and 53% of non-pregnant women to be moderately iodine deficient. A study of UK schoolgirls found that 51% were mildly iodine deficient and 16% were moderately deficient. Importantly, the prevalence of iodine deficiency was highest in Northern Ireland where 85% of those sampled were iodine deficient.